Method of lining bearings with molded bushings



L. c. MILLER July7, 1953 METHOD OF LINING BEARINGS WITH MOLDED BUSHINGS Filed Sept. 5, 1950 k 1 u l/l/l/l/JO! I R .5 ML M H.. c R E T S a L Patented July 7, 1953 MOLDED BUSHINGS:

Lester Miller? MjIWauKeBJiWiiSL E. R, Wagner Manufacturing to ram;

waukee"; Wlsj jamorporati'on 0 Wisconsin; Application September 5, magseraim. ratios 1 fr is iri enti n r a es to i reveme ts nwt m thod f making e earinesi, r c rly 11 th .typeeh ving, ametallic shell n neeetal i L ynthetic bushin 4 ,w Bearings of thistype have been madeby pressing previously moulded synthetic bushings made 'of.,hi h molecular we h 1e 'm v ch s de- -,scribe d inll. S. Patent 2,245,086, or of high m olecu1a1u,wei ht. ethylen po ymers, such c as dei erib dzmil. Ea ent 2,2e6. 92,;,i to. a met shell... such. syntheti bush gs ar ..m d ye comparatively expensive injection moulding -procesS,'.1'. ,q1l-i1i ng....t ,e use of .a virnflt pl y .o f ex- .--D ,nsive .diese inmorderntol produce a variety of "shapes andsizesloibearingst 1 1, Itis anioloie t. of I this. inv nt on, the for t provide ,a bearing hetvm ia synthetic bushing .lwhichtiis comparatively inexpensive to manufact reand. mar-he readily made; in a variety of sizes 'l V v v V o. o.

his .ObjectiS Obtainedby iorming lengths of Standard 0mm c a1...s c tions oiextruded synthetic material, such, aser above: described, into circlesgeor rings ,of predetermined size, pl a cin -such rin s-tin a diehaipartoj which. die

consists}. of the metallic,v shell of; the bearing,

-. a pp yin without additional heatisu ficient .pressure .on; Suchjdie, to impact mou1 s i ripe with n sa metallic, she .v intmthe .iinal;

desired. The bearing so formedjseil egpensively 3 made because of the comparatively loyy eost anrzl avaflabil-itvnf standard..extrudin lliormsl T h .as ro sh q res, re tan les, orvribbon andh ,cause thevassemhlymstepwis a s the mou ding shaping st p. c l c v ,7 .7 Y The novel -features whichare considered eh;a r' ae eristic. of the inventionareset ferth..w th periti la ity n t a p nde aims-t The. inv no tion itself, ,hovvever, both, as to its organization and its method of operation, together withadditional objects and advantages thereof, will best" be understood from the following description of asp'ecifie einbodimeht 'when read in connection with thegaccornpanying drawings in which:

Rig, 1 is a view in front elevation of a bearing embodying the present invention; Fig. 2"'isia"'sect'ional'view'taken on Fig..1';' .11" Fig. 3 is a view'in rearoelevation 0i thebearing viewed in Fig. 1'; t Fig. 4 is a fragmentary sectional view, of the" \.-tool by which the syntheticbushing is impact I mouldedwithin the metallic shell with'the parts shown prior to the pressing operation;

Fig. 5 is aview' similar to 1 c ai (01. 18 512 19 as are used for ba 15. the testin Fig. 4 witff'b artsf 2 the. rel tee iqne ume h hasloeeriicor'n ileted; and [fragmentary sectional view taken .f-FIFigJZL :Qrrlirie 6.

5 J'Ijhecbearmg' described herein consist sfofla n Te t r "-etam shell .1 o and a non-metallic. synthetici'b ishing fl6-i" Because. offlthe particiilar ,shape ffthisjshelh the'bearing'is adapted for use'incorinection with lightweight wheels such f carriag miare rsverceipefdes "ah'dthe 111; ;;I-Iowever, yariofissl'ia shells may be usa'depenamg 'lipontlieiiltimate purpose for which thebearing isto be used The important 'coin monfcharacteristic of all shells is s pport Lor necli I 2 of hollow c'sil'irifdrical "shaiie centrally; located in the shell. "This provides v"radi iipnort forfthe onshingiorfsififi cient lfiIiQllh t6 provide suitable tbearing area. The shelliflfl is a punched metal ,part. made in a well-known manner? with suitable "tools and presses which [form'the heck l2 'as the "shell'is made. 1; ,lmafi'r'j be desirable to. provide ears I 4 which project iroih oneedge oflthe nck'lZ.

'Ifhesele'ars'ihtelrlocli ,with the synthetic 'biishing lat pr vntrelat'iv'irdtatioiibetween siieiiaiid .bii h n" i; The non metallic synthetic bushin .ime icte i m e ie m. the n c e sharieis inthemahn'er hereinafter described. a f oin material. known to the trade; as bitainedf 'IrQrnI-EJJI. du .Porit'ae c.) L "In its completedos hape 5 S cunew'abouti it'sl'ld'ng'itfid ifial th sl es a ili es: n lt qil l extending" sea "20.. It, has' a'. central tub. I part withfrelativelyl thiri wall sections whichilie aga'inst ari a e radially supported by the inner I fi eneek J2- Theii t-en Q ji 11"eia i ter;r tainin at iidh urge; 'diaifne't'erfret s se j riahgesieneaee' o osi e. end 1 L a ap-to t the; Bflshingagainstlohsp aoemeh twithresfiect to suchneck. friiefeq hindmoulwfariiiforming x661 fused or impact .nionlding the T ,nonmetallic 'busfiihg Lit 2 gitridihalld 45 itflviithiiiith neck. I 2..wi11fnow be described f t .4 w

shown in Figs. 4 and 6. is applied so that the die ring 36 and sleeve 32 properly seat within and against the shell and force it against the pressure pad 24. is suflicient resistance applied to the pressure 3 end of the punch-receiving opening in the pressure pad 24. The purpose of this ring is to equalize pressures along its top and thus provide.

a tight seal between the end of the neck l2 and the pad 24 to prevent the non-metallicbushing material from flowing therebetween and forming undesirable flashing. Another element of the mould and tool is a die ring which fits within the metallic shell [6 in such a way as to provide support for the neck l2 during impact moulding. A sleeve 32 mounted within the ring 30 has an opening 34 which tightly receives the tip of the punch 22.

determines the distance between the bottom of the sleeve 32 and the top of the neck [2 when the mould and tool with the shell therein isin fully closed position. This distance controls the thickness of the small retaining flange on the 'front end of the bushing. As is customary with this type of tool, stripper. pins 65 may ,be provided by which the completed bearing smay be When the tip is in such opening far enough to make a seal therebetween the mould is closed. A shoulder on the sleeve-32 on the bushing l6 as completed and this indicates that the material while being impact moulded is fluid enough to attempt to flow out of any crevices or spaces between adjoining sections of the mould. During the impact moulding the material ,whichflows into 'the small diameter flange of the bushing l6 forms around the ears M and thus provides a good interlock between such bushing and the shell preventing relative rotation therebetween; As 'the neck [2 and its ends are a part of the mould the material of the bushing l6 rests snugly against the surface of the neck I 2. This makes a tight fit be- 'tween the bushing and the shell so that the bushing is supported both radially and longitudinally.

ejectedfrom the die ring; The pressureipad" 24 ent parts 'of the tool may be-made from metals 'havi characteristics designed to provide good sealsrtherebetween and still have a long useful life..

The'first step in making a bearing with the mould and tool as described is to pre-form a ring I 8 of the syntheticmateria'l heretofore de- :3. scribed. In this particular embodiment ofv the also acts asstripper when thepunch 22 is moved downwardly relative thereto and pulls thecompleted bearing from the tip of the punch. In 1 accordance with well-known practice, the differinvention such ring is made froman extruded 1 rod of nylon of a commercial size available for purchase from stock on the open market; The 1 j rod isbent around a mandrel until a ring is formed'and then such ring is cut from the rod.

The ring so formed has an inside diametersufilcient to permit the, ring to fit over the tip of the punch 22 andan outside diameter small j enough topermit-the ring to fit within the punch opening in the pressure pad 24. The second step is to pla'ce'the'ringfl ii on the, tip of the punch 22 while the tool is open and before the metallic shell I6 is put in place. Next the metallic shell [0 is placed in the'recess 26 over "th'e ring I8 as Then impact pressure There pad 24 by way of springs or other instrumentality (not shown) to effectively cause such seating action. Thereafter continuation of such pressure causes the die ring 30, sleeve 32, shell I0, and pressure pad 24 to move as a unit relative to the punch 22. the sleeve 32 applying pressure to the ring l8 1 and closing the mould. While no outside heat is added the pressure and the resultant heat created solely thereby are enough-to cause the synthetic material in the'ring l8 to become sufii- The tip of the'punch is forced into ciently fluid so that such material flows while in themould and assumes the new shape of the bushing l6 shownin the drawings. In the com- 'pleted bushing the seam 20 only elongates and does not disappear; This indicatesthat' the material does not become fluid enough to run together as would be the case if a bushing were made by the high temperature injectionmoulding process. However, there are some flash edges It is not essential to this invention that the ring 18 be formed from extruded rod, Other standard commercially extruded sections may be used such as ribbon, hexagonal, or bar. The

only requirement is to have enough cubic area in the ring 18 to substantially fill the cubic area of the, closed mould in order to make the desired fnew form 'of bushing. The cost of standard commercially extruded sections of the synthetic material plus the-labor of impact moulding as here described is considerably less than the costof making'a synthetic bushing by the injection moulding process.

v This is so whether such bushing is injection moulded into a special metal shell or ,made separately and spring-forced into place with a metal shell. The bushing described herein cannot be made from synthetic material in the powder form without more expensive type of tools and the special application of additional heat, The necessity of such additional heat is not only expensive of itself but it increases the moulding time per unit.- The steps :of this inventionshaping standard-stock into a-ring and impact moulding such ring into the a desired shape of bushing using the metallic shell as part of the mould-are relatively few, sim- -ple, and rapidly performed,-and, therefore, produ-ce an inexpensive highly efficient bearing.

Although onlyone embodiment of the inven- I tion is shown anddescribed herein, it will be understood that-this application is intended to 7 within the spirit of the invention or cover such changes or modifications as come scope of the following claim.

I claim: The method of making a bearing comprising forming a section of nylon rod into a split ring,

placing said split ring on the tip of a punch,

forcing said tip into a metallic neck while applying reactive pressure on said neck to cause the synthetic material in'said ring to flow and form a split bushing having a hollow cylindrical I portion within said neck and retaining flanges at each end of said'neck.

, I LESTER C. MILLER.

References Cited in the file of this patent UNITED STATES PATENTS 

